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Fly Trucks

How to make them handle

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#1 Sports Racer

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Posted 28 April 2019 - 11:50 AM

A couple of the clubs I race with are running Trucks and there's a few that are pretty quick. Here's how I've set up mine.

This Buggyra is a flat out racer. I don't think I can do anything else to make it faster and it drives like a well set up 1/24 Scaleauto. It could do with a lot more power but the class is limited to the Standard Fly truck motor or a Ninco NC5. On home tracks it laps faster than any Scalex GT.

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Rear tyres are Yellowdogs off a Carrera Canam. It sits so low I had to shave the bottom of the body to clear the track.

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This is all the weight it needs and you can see how much I've gutted the sides of the chassis to remove excess weight. I had to cut off the lower part of the chassis near the rear axle as well - it scraped the track.

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My Sisu laps 1/10 sec faster on the big 8 lane track at Way2fast in Canberra but it's not as stable.

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This is how much lead it used to need.

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It's getting a few chassis mods to lower it.

Pictures to come.

Paul

Edited by Sports Racer, 28 April 2019 - 09:27 PM.

May the downforce be with you.

#2 Sports Racer

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Posted 28 April 2019 - 12:40 PM

If you take the body off a truck it's basically a 1/24 car and handles as well (damn good) so it's the height that makes them pigs through corners. I thought if I can get this truck as low as possible it has to handle better than standard.

I started with one of Munter's excellent rear U brackets which fits easily inside the chassis.

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I soldered a couple of brass plates to get it sitting at the right ride height (low) and to use as a rear mount for the bracket. Rear tyres are MJK truck tyres on the MJK 1 piece alloy wheel.

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The front axle needed to be raised to match the new ride height of the rear, easily done with a few pieces of scrap plastic glued in with 5 minute Araldite. There's only 10g of lead inside, a bit more under the chassis but not much.

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You can see how much the rear axle has been raised. I kept the front motor mount which had the added advantage of lowering the front of the motor with the chassis. Got to keep the weight low. There's less than 2mm ground clearance now.

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This is how it sits now. The rear arches have been opened up to clear the tyres and there's not much clearance between the rear tyres and the bodywork.

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It needs a lot less lead as well. Under the chassis there's a bit in the recess behind the guide and a strip across the front.

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Initial testing on a 3 lane home track shows great potential. Very stable and now gives Revoslots a hard time - it stays with them through the corners.

Edited by Sports Racer, 28 April 2019 - 08:20 PM.

May the downforce be with you.

#3 Pedro51

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Posted 28 April 2019 - 04:58 PM

Thanks for this, we no longer race trucks but I feel a trip to the workbench for a couple of mine, or maybe 3 so I can run them as a house class. I have a couple with NSR Ultragrips fitted that would benefit greatly from lowering.

#4 Sports Racer

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Posted 28 April 2019 - 07:30 PM

Ultragrips might be too good for your trucks. These big rigs need to slide a bit through corners so they don't tip over.

The next one on my "to do" list is going to be a copy of this.

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It's another Sisu but with a 3D chassis from JS chassis designs. You'll find them on Facebook.

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This one was built by one of the guys I race with and it took him 17 hours of building/tuning to get it competitive. There is no separate pod on the chassis but it does have a piece that flexes so it acts like a pod. While this may work well on cars it isn't what you want with a truck - gave it too much grip and it was lifting a front wheel through corners. It wasn't until the thing was glued to make it flexless that it started to handle better.

The 3D chassis sits low like my modified chassis and I think that's why it handles well.

This what you get from JS, just add your Sisu bits.

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Edited by Sports Racer, 28 April 2019 - 08:10 PM.

May the downforce be with you.

#5 Sports Racer

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Posted 28 April 2019 - 08:42 PM

I've just noticed that there's ribs on the bottom of the chassis that can be sanded down so the bottom of the chassis is completely flat.

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That means I can lower it more. :)

I also need to trim that front axle, way too wide.

Edited by Sports Racer, 28 April 2019 - 08:44 PM.

May the downforce be with you.

#6 gazza

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Posted 30 April 2019 - 05:31 PM

Nice one Paul
Quickly read this post before it is deleted or i turn grey again

Gary

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